#include <bits/stdc++.h>

#define eb emplace_back
#define ep emplace
#define fi first
#define se second
#define in read<int>()
#define lin read<ll>()
#define rep(i, x, y) for(int i = (x); i <= (y); i++)
#define per(i, x, y) for(int i = (x); i >= (y); i--)

using namespace std;

using ll = long long;
using db = double;
using pii = pair < int, int >;
using vec = vector < int >;
using veg = vector < pii >;

template < typename T > T read() {
	T x = 0; bool f = 0; char ch = getchar();
	while(!isdigit(ch)) f |= ch == '-', ch = getchar();
	while(isdigit(ch)) x = x * 10 + (ch ^ 48), ch = getchar();
	return f ? -x : x;
}

template < typename T > void chkmax(T &x, const T &y) { x = x > y ? x : y; }
template < typename T > void chkmin(T &x, const T &y) { x = x < y ? x : y; }

const int N = 1e6 + 10;

int n, l[N], r[N];
int a[N];

void solve() {
	n = in; rep(i, 1, n) l[i] = in, r[i] = in, a[i] = 0;
	int ret = 0;
	per(j, 30, 0) {
		bool ok = 1;
		rep(i, 1, n) ok &= ((a[i] | (1 << j)) <= r[i]);
		if(ok) {
			ret |= 1 << j;
			rep(i, 1, n) a[i] |= 1 << j;
		} else {
			rep(i, 1, n) if(!(a[i] >= l[i]) && l[i] >> j & 1) a[i] |= 1 << j;
		}
	} printf("%d\n", ret);
}

int main() {
#ifdef YJR_2333_TEST
	freopen("1.in", "r", stdin);
#endif
	for(int T = in; T; T--) solve(); return 0;
}
